Should I release any BSTR objects which the Inventor API gives me?

[oransen]

Am I right in assuming that any BSTR objects returned to me from the Inventor API should be released with a call to SysFreeString?

And that rule should be followed whether I use a ->GetThingy() or ->get_Thingy() format?

[wayne.brill · Accepted solution]

Hi,

I would say that you should use SysFreeString(). I find this done in several places in the Inventor SDK. One is in AtlAddinServer.h and in RevisionCloudCmd.cpp in this folder on my system:

C:\Users\Public\Documents\Autodesk\Inventor 2014\SDK\UserTools\DrawingTools\Source 

HRESULT CRevisionCloudCmd::ChangeLabelName(CComPtr<DrawingSketch> pSketch)

{

BSTR DisplayName;

HRESULT hr = pSketch->get_Name(&DisplayName);

OnErrorReturn(FAILED(hr),hr);

CString ReplaceDisplayName;

int len = SysStringLen(DisplayName);

for(int i = 6;i<len;i++)

ReplaceDisplayName += DisplayName[i];

ReplaceDisplayName.Insert(0,_T(

"RevisionCloud"));

BSTR ReplacedDisplayName = ReplaceDisplayName.AllocSysString();

hr = pSketch->put_Name(ReplacedDisplayName);

SysFreeString(ReplacedDisplayName);

ATLASSERT(SUCCEEDED(hr));

SysFreeString(DisplayName);

return hr;

}

Thanks,

[oransen]

Thanks! It makes sense, but I wanted to be sure.